[FIX] website_sale: performance imp to search abandoned carts

By removing the `.id` from the `partner_id.id` domain leaf,
the ORM avoids to do a useless `SELECT` to read
the id of all partners different from the public partner,
as it already got the information from the `sale_order` table

e.g
Here is the SQL request before the revision:
```
SELECT "sale_order".id FROM "sale_order" WHERE ((((("sale_order"."date_order" <= %s)  AND  ("sale_order"."team_id" in (%s)))  AND  ("sale_order"."state" = %s))  AND  ("sale_order"."partner_id" in (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)))  AND  ("sale_order"."id" in (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s))) ORDER BY "sale_order"."date_order" DESC,"sale_order"."id" DESC
```
Here it is after:
```
SELECT "sale_order".id FROM "sale_order" WHERE ((((("sale_order"."date_order" <= %s)  AND  ("sale_order"."team_id" in (%s)))  AND  ("sale_order"."state" = %s))  AND  ("sale_order"."partner_id" != %s))  AND  ("sale_order"."id" in (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s))) ORDER BY "sale_order"."date_order" DESC,"sale_order"."id" DESC
```

closes odoo/odoo#28927

addons/website_sale/models/sale_order.py

@@ -64,7 +64,7 @@ class SaleOrder(models.Model):
             ('date_order', '<=', abandoned_datetime),
             ('team_id.team_type', '=', 'website'),
             ('state', '=', 'draft'),
-            ('partner_id.id', '!=', self.env.ref('base.public_partner').id),
+            ('partner_id', '!=', self.env.ref('base.public_partner').id),
             ('order_line', '!=', False)
         ])
         # is_abandoned domain possibilities